<p>A chain of <code>if</code>/<code>else if</code> statements is evaluated from top to bottom. At most, only one branch will be executed: the first
one with a condition that evaluates to <code>true</code>.</p>
<p>Therefore, duplicating a condition automatically leads to dead code. Usually, this is due to a copy/paste error. At best, it’s simply dead code and
at worst, it’s a bug that is likely to induce further bugs as the code is maintained, and obviously it could lead to unexpected behavior.</p>
<h2>Noncompliant Code Example</h2>
<pre>
if (param == 1)
  openWindow();
else if (param == 2)
  closeWindow();
else if (param == 1)  // Noncompliant
  moveWindowToTheBackground();
}
</pre>
<h2>Compliant Solution</h2>
<pre>
if (param == 1)
  openWindow();
else if (param == 2)
  closeWindow();
else if (param == 3)
  moveWindowToTheBackground();
}
</pre>
<h2>See</h2>
<ul>
  <li> <a href="https://wiki.sei.cmu.edu/confluence/x/5dUxBQ">CERT, MSC12-C.</a> - Detect and remove code that has no effect or is never executed
  </li>
</ul>

